#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define bug(a) cout << #a << " : " << a << endl;

vector<pair<ll,ll>> point;
pair<ll,ll> p;

ll tri_sum(pair<int,int> p1,pair<int,int> p2){
   ll sum = (p1.first*p2.second + p2.first * p.second + p.first*p1.second);
   sum -= (p1.second*p2.first + p2.second * p.first + p.second*p1.first);
   return abs(sum);
}
ll get(){

	ll sum1 = 0, sum2 = 0;
	int n = point.size();
	for(int i = 0; i < n; i++){
		if ( i == n-1 ) {
			sum1 += (1LL * point[i].first * point[0].second);
		}
		else{
			sum1 += (1LL * point[i].first * point[i + 1].second);
		}

		if ( i == n-1 ) {
			sum2 += (1LL * point[i].second * point[0].first);
		} 
		else {
			sum2 += (1LL * point[i].second * point[i + 1].first);
		}
	}
	ll ans = abs(sum1 - sum2);
	return ans;

}

void solve(){
	int n;	cin >> n;

	for(int i = 1; i <= n; i++){
		int x, y;	cin >> x >> y;
		point.push_back({x, y});
	}

	
	cin >> p.first >> p.second;

	ll area = get();

	ll area_upd = 0;
	for(int i = 0; i < n;i++){
	if(i == n-1){
		area_upd += tri_sum(point[i],point[0]);
	}
	else
	    area_upd += tri_sum(point[i],point[i+1]);
	}
	

	if(area == area_upd){
		cout << "YES" << endl;
	}
	else{
		cout << "NO" << endl;
	}
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

	int tc = 1, cs = 0;
	// cin >> tc;

	while(tc--){
		//cout << "Case # " << ++cs << ": " ;
		solve();
	}

}